1. Field of the Invention
The invention relates construction machines, and more particularly; to a crawler undercarriage for a construction machine.
2. Description of the Related Art
Such crawler undercarriages generally have two undercarriage halves connected to one another via a frame. One undercarriage half essentially comprises a closed chain with base plates, which runs over a tumbler and idler wheel by means of an interposed supporting frame with a chain tensioning device and, for lower guidance, has track rollers along the supporting frame and, for upper guidance, has carrier rollers.
A carrier roller generally comprises a wheel body portion on the two side faces of which bearing pins are coaxially arranged. The carrier roller is mounted in a rotating manner on the upper part of the supporting frame by means of the bearing pins and corresponding bearings. The carrier roller prevents the chain from rubbing against the supporting frame. The chain rests on the carrier roller and, for guidance, has driving cams, which are shaped in such a way that the wheel body portion of the carrier roller engages in a groove-like portion of the driving cams of the chain. Consequently, an unfavorable movement of the chain transversely with respect to the running direction is avoided. There is frictional engagement between the chain and the carrier roller. Particularly under extreme environmental influences, such as in opencast operation for example, disturbances of the frictional engagement may occur, with the result that it is possible for the carrier roller to come to a standstill. This has the consequence of considerable wear on the carrier roller and on the chain, with the result that the service life of the two components is reduced.
DE 296 16 953 U1 discloses a carrier roller which interacts in a positively engaging manner with a chain in order to avoid the carrier roller coming to a standstill during operation. For this purpose, the carrier roller has cam-like projections on its outer circumference, which engage in recesses present between individual chains links. This type of design does indeed prevent the carrier roller from coming to a standstill on account of the positive engagement; since, however, a relative movement of the two engaged components can take place in the case of the previously known solution on account of the engagement geometry of the carrier roller and chain, here too there is a tendency toward wear. Furthermore, the carrier roller is a quite complex structural design, in particular because of the radially outer cam-like projections, which are fastened on the carrier roller by bolting or by clamping.